In recent years, a variety of services such as a speech command system, a speech search system, and a speech interaction system which operate on reception of human utterances along with the advance of speech processing techniques have been used. A human utterance, that is, the spoken language does not have a clear breakpoint such as punctuation marks included in the written language. To provide the above services, a received utterance must be divided into units suitable for such a service. As a technique of dividing the utterance into appropriate processing pieces suitable for such a service, a technique of dividing an utterance including a pause given as a voiceless section into processing pieces is available.